A conventional refrigerating compressor includes a suction muffler open into a hermetic container for sucking refrigerant gas. The suction muffler has a resonating chamber, thereby reducing sounds at a specific frequency. An instance is disclosed in Japanese Patent Unexamined Publication No. H10-184542 (hereinafter referred to as “patent document 1”). The conventional refrigerating compressor is described hereinafter with reference to accompanying drawings.
FIG. 6 shows a partially cutaway perspective view illustrating an entire construction of the conventional refrigerating compressor disclosed in patent document 1. FIG. 7 shows a partially cutaway perspective view illustrating parts of a compressing element and a suction muffler to be used in the conventional refrigerating compressor.
In FIGS. 6 and 7, hermetic container 1 (hereinafter referred to simply as “container 1”) pooling lubricant (not shown) accommodates compressing member 20 supported by elastic member 6 such as a spring. Compressing member 20 has motor element 2 and compressing element 3 disposed under and over frame 5 respectively. Frame 5 includes a bearing (not shown) for supporting a crank shaft (not shown) unitarily molded with crank pin 4.
Crank pin 4 (hereinafter referred to simply as “pin 4”) is eccentrically fastened into the crank shaft press-fitted into a rotor (not shown) of motor element 2. Piston 7 is inserted in cylinder 8 and is able to reciprocate. Coupling means 9 couples piston 7 to pin 4.
Valve plate 10 (hereinafter referred to simply as “plate 10”) having a suction port (not shown) seals an end face of an opening of cylinder 8. Opening of the suction valve allows the suction port to communicate with cylinder 8. Cylinder 8, a top plate of piston 7 and plate 10 form a compressing chamber (not shown).
Cylinder head 11 (hereinafter called simply as “head 11”), in which a high pressure chamber is formed, is rigidly placed opposite to cylinder 8 via plate 10 in between. Suction muffler 12 includes tail tube 13 and resonator 16. Tail tube 13 opens into container 1, and refrigerant gas is sucked through tail tube 13. Resonator 16 has resonating chamber 15 communicating with tail tube 13 and throttle hole 14. A first end of communicating tube 17 is coupled via head 11 to the suction port disposed on plate 10, and a second end thereof is coupled to suction muffler 12.
An operation of the refrigerating compressor discussed above is described hereinafter. Motor element 2 drives the crank shaft, so that pin 4 starts eccentric movement, which reciprocates piston 7 via coupling means 9 in cylinder 8. Then the steps of sucking refrigerant gas, compressing the gas, and discharging the gas are sequentially repeated in the compressing chamber.
In the sucking step by piston 7, the refrigerant gas filled in container 1 is sucked from an opening of tail tube 13. The gas sucked then travels to the suction port via a suction path formed of muffler 12, communicating tube 17 and head 11. The gas further pushes the suction valve, which closes the suction port, open and flows into cylinder 8. When the refrigerant gas flows into cylinder 8, the suction valve vibrates and the gas ripples, thereby producing noises. Sound in low frequency band (approx. 400 Hz-600 Hz) out of the noises can be deadened by resonator 16.
In the recent application, a refrigerating compressor having more excellent sound deadening characteristics is required.